Light emitting device and illumination apparatus having same

Abstract

A light emitting device includes a set of light source units including multiple types of solid state light emitting elements having different light colors, each of the light source units comprising the same type of the solid state light emitting elements connected in series and; and an information storage unit which stores information about electrical characteristic of the set of light source units. The information stored in the information storage unit represents a relationship between a light output and a drive current in the set of light source units.

What is claimed is: 
     
       1. A light emitting device comprising:
 a set of light source units including multiple types of solid state light emitting elements having different light colors, each of the light source units comprising the same type of the solid state light emitting elements connected in series; and 
 an information storage unit including at least one circuit element which stores information about electrical characteristic of the set of light source units for the information to be transmitted to an illumination apparatus after connection of the light emitting device to the illumination apparatus, 
 wherein the information represents a relationship between a light output and a drive current of the set of light source units and represents an error in the drive current of the set of light source units due to a difference in a production lot or a use environment of the solid state light emitting elements such that, when the information is transmitted to the illumination apparatus after connection of the light emitting device to the illumination apparatus, the illumination apparatus determines the drive current provided to the light emitting device based on the information to suppress a variation in the light output of the set of light source units due to individual variations among the solid state light emitting elements. 
 
     
     
       2. The light emitting device of  claim 1 , wherein the information storage unit includes one or more resistive elements having a resistance value corresponding to the information. 
     
     
       3. The light emitting device of  claim 2 , wherein the information storage unit further includes the resistive elements; and switch elements which separately switches on and off conduction of the resistive elements. 
     
     
       4. An illumination apparatus comprising:
 the light emitting device described in  claim 1 ; 
 a power supply unit which individually supplies the drive current to each of the light source units of the light emitting device; and 
 an adjusting unit which obtains the information stored in the information storage unit, and adjusts the drive current supplied from the power supply unit to each of the light source units based on the obtained information. 
 
     
     
       5. An illumination apparatus comprising:
 the light emitting device described in  claim 2 ; 
 a power supply unit which individually supplies the drive current to each of the light source units of the light emitting device; and 
 an adjusting unit which obtains the information stored in the information storage unit, and adjusts the drive current supplied from the power supply unit to each of the light source units based on the obtained information. 
 
     
     
       6. An illumination apparatus comprising:
 the light emitting device described in  claim 3 ; 
 a power supply unit which individually supplies the drive current to each of the light source units of the light emitting device; and 
 an adjusting unit which obtains the information stored in the information storage unit, and adjusts the drive current supplied from the power supply unit to each of the light source units based on the obtained information.